Chng Tat Loon, Naphade Maya, Goldberg Benjamin M, Adamovich Igor V, Starikovskaia Svetlana M
Opt Lett. 2020 Apr 1;45(7):1942-1945. doi: 10.1364/OL.45.001942.
Electric-field-induced second-harmonic generation, or E-FISH, has received renewed interest as a nonintrusive tool for probing electric fields in gas discharges and plasmas using ultrashort laser pulses. An important contribution of this work lies in establishing that the E-FISH method works effectively in the nanosecond regime, yielding field sensitivities of about a kV/cm at atmospheric pressure from a 16 ns pulse. This is expected to broaden its applicability within the plasma community, given the wider access to conventional nanosecond laser sources. A Pockels-cell-based pulse-slicing scheme, which may be readily integrated with such nanosecond laser systems, is shown to be a complementary and cost-effective option for improving the time resolution of the electric field measurement. Using this scheme, a time resolution of ∼3 ns is achieved, without any detriment to the signal sensitivity. This could prove invaluable for nonequilibrium plasma applications, where time resolution of a few nanoseconds or less is often critical. Finally, we take advantage of the field vector sensitivity of the E-FISH signal to demonstrate simultaneous measurements of both the horizontal and vertical components of the electric field.
电场诱导二次谐波产生（E-FISH）作为一种使用超短激光脉冲探测气体放电和等离子体中电场的非侵入性工具，重新引起了人们的关注。这项工作的一个重要贡献在于证实了E-FISH方法在纳秒 regime 中有效工作，在大气压下，从16纳秒脉冲可产生约1千伏/厘米的场灵敏度。鉴于传统纳秒激光源更容易获得，这有望扩大其在等离子体领域的适用性。一种基于普克尔盒的脉冲切片方案，可轻松与此类纳秒激光系统集成，被证明是提高电场测量时间分辨率的一种补充且经济高效的选择。使用该方案，可实现约3纳秒的时间分辨率，而不会对信号灵敏度造成任何损害。这对于非平衡等离子体应用可能具有极高价值，在这些应用中，几纳秒或更短的时间分辨率通常至关重要。最后，我们利用E-FISH信号的场矢量灵敏度来演示电场水平和垂直分量的同时测量。
